A TCXO is actually a crystal oscillator which contains a temperature-delicate reactive circuit in its oscillation loop that compensates for inherent temperature variations that come about each time a crystal oscillator is in use. Other than the direct temperature variation, thermal and temperature gradients in TCXOs influence the secure operation https://felixrftiw.livebloggs.com/37250632/little-known-facts-about-tcxo-oscillators